Methods of forming integrated circuitry

ABSTRACT

Some embodiments include a method of forming integrated circuitry. A structure has first conductive lines over a dielectric bonding region, has semiconductor material pillars extending upwardly from the first conductive lines, and has second conductive lines over the first conductive lines and extending along sidewalls of the semiconductor material pillars. The first conductive lines extend along a first direction, and the second conductive lines extend along a second direction which intersects the first direction. The structure includes semiconductor material under the dielectric bonding region. Memory structures are formed over the semiconductor material pillars. The memory structures are within a memory array. Third conductive lines are formed over the memory structures. The third conductive lines extend along the first direction. Individual memory structures of the memory array are uniquely addressed through combinations of the first, second and third conductive lines.

RELATED PATENT DATA

This patent resulted from a continuation of U.S. patent application Ser.No. 16/421,242 which was filed May 23, 2019, which is a continuation ofU.S. patent application Ser. No. 15/923,864 which was filed Mar. 16,2018, each of which is hereby incorporated by reference herein.

TECHNICAL FIELD

Methods of forming integrated circuitry; such as, for example, methodsof forming memory architectures having monocrystalline semiconductormaterial within channel regions of access devices.

BACKGROUND

Transistors may be utilized in numerous applications; such as, forexample, dynamic random-access memory (DRAM), resistive RAM (RRAM),magnetic RAM (MRAM), spin-transfer-torque-MRAM (STT-MRAM), etc.

A field-effect transistor (FET) comprises a gated channel region betweena pair of source/drain regions.

A continuing goal of semiconductor fabrication is to increase thedensity of integration. It is therefore desired to develop improved FETarchitectures which are suitable for utilization in highly-integratedarchitectures, and to develop methods for fabricating such FETarchitectures.

Wafer bonding is a methodology which may have application relative tointegrated assemblies. Wafer bonding comprises the bonding of twosemiconductor assemblies to one another to form a composite structure.One method of wafer bonding comprises formation of silicon dioxidesurfaces across each of the assemblies which are to be bonded to oneanother. The silicon dioxide surfaces are then placed against oneanother, and subjected to appropriate treatment to induce covalentbonding between the surfaces and thereby form the composite structure.The treatment utilized to induce the covalent bonding may be a thermaltreatment. In some applications, such thermal treatment may utilize atemperature in excess of 800° C. Alternatively, one or both of thesilicon dioxide surfaces may be subjected to a plasma treatment prior tothe thermal treatment, and in such aspects the temperature of thethermal treatment may be reduced to a temperature within a range of fromabout 150° C. to about 200° C. The bonding of the silicon dioxidesurfaces to one another may be referred to as “fusion bonding”.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-10 are diagrammatic three-dimensional views of an exampleintegrated arrangement at example process stages of an example methodfor fabricating integrated circuitry.

FIG. 11 is a diagrammatic three-dimensional view of the integratedarrangement of FIG. 10 showing relevant structures of a memory array.

FIG. 12 is a diagrammatic cross-sectional side view across severalneighboring access devices of an example memory array and illustratesexample programming modes associated with the access devices.

FIG. 13 graphically illustrates example current and voltagecharacteristics of the programming modes of FIG. 12.

FIG. 14 is a diagrammatic three-dimensional view of an exampleintegrated arrangement showing peripheral circuitry coupled with aregion of the example access devices of FIG. 12.

FIG. 15 schematically illustrates a region of an example memory array,and a region of peripheral circuitry adjacent to the memory array.

FIGS. 16-26 are diagrammatic three-dimensional views of an exampleintegrated arrangement at example process stages of an example methodfor fabricating integrated circuitry.

FIG. 27 is a diagrammatic three-dimensional view of the integratedarrangement of FIG. 26 showing relevant structures of a memory array.

FIG. 28 is a diagrammatic three-dimensional view of another exampleintegrated arrangement.

FIG. 29 schematically illustrates a region of an example memory array,and a region of peripheral circuitry adjacent to the memory array.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Vertical transistors are transistors in which a channel region extendsvertically between source/drain regions. Vertical transistors may beutilized as access devices in highly-integrated memory architectures. Itmay be simpler to incorporate polysilicon into channel regions ofvertical transistors than to incorporate single crystal silicon (i.e.,monocrystalline silicon) in the channel regions. However, polysiliconcan cause malfunctions in memory performance due to, for example,deviations in transistor resistance with increasing miniaturization.Some embodiments include recognition that it would be advantageous toincorporate monocrystalline silicon into channel regions of verticalaccess transistors. Some embodiments include new methods in which waferbonding (i.e., fusion bonding) techniques are utilized to enablevertical access transistors to be formed with monocrystalline siliconacross active regions of the transistors (i.e., across the channelregions and source/drain regions of the transistors). Althoughmonocrystalline silicon is recognized as a desirable material for activeregions of vertical transistors, it is also recognized that othersemiconductor materials may be suitable in some applications.Accordingly, it is to be understood that embodiments described hereinmay to be suitable for utilization with monocrystalline silicon and/orwith other semiconductor materials. Example embodiments are describedwith reference to FIGS. 1-29.

Referring to FIG. 1, a construction 10 includes a mass 12 ofsemiconductor material 14. The semiconductor material 14 may compriseany suitable composition(s); and in some embodiments may comprise,consist essentially of, or consist of one or more of silicon, germanium,III/V semiconductor material (e.g., gallium phosphide), semiconductoroxide, etc.; with the term III/V semiconductor material referring tosemiconductor materials comprising elements selected from groups III andV of the periodic table (with groups III and V being old nomenclature,and now being referred to as groups 13 and 15). In some embodiments, thesemiconductor material 14 may comprise, consist essentially of, orconsist of single crystal silicon (i.e. monocrystalline silicon). Insome embodiments, the semiconductor material 14 may be referred to as afirst semiconductor material to distinguish it from other semiconductormaterials formed at later process stages.

The mass 12 includes a first conductively-doped region 16 over a secondconductively-doped region 17. One of the regions 16 and 17 is n-typedoped while the other is p-type doped. In the shown embodiment, theupper region 16 is n-type doped, while the lower region 17 is p-typedoped. In other embodiments, the doping of regions 16 and 17 may bereversed so that the lower region 17 is n-type doped and the upperregion 16 is p-type doped. Although the doped regions 16 and 17 areshown to be provided at the process stage of FIG. 1, in otherembodiments one or both of such doped regions may be provided at a laterprocess stage.

In some embodiments, the mass 12 may be considered to be an example of asemiconductor substrate. The term “semiconductor substrate” means anyconstruction comprising semiconductive material, including, but notlimited to, bulk semiconductive materials such as a semiconductive wafer(either alone or in assemblies comprising other materials), andsemiconductive material layers (either alone or in assemblies comprisingother materials). The term “substrate” refers to any supportingstructure, including, but not limited to, the semiconductor substratesdescribed above.

Referring to FIG. 2, conductive lines 18 are formed over thesemiconductor material 14. The conductive lines 18 comprise conductivematerial 20. The conductive material 20 may comprise any suitableelectrically conductive composition(s); such as, for example, one ormore of various metals (e.g., titanium, tungsten, cobalt, nickel,platinum, ruthenium, etc.), metal-containing compositions (e.g., metalsilicide, metal nitride, metal carbide, etc.), and/or conductively-dopedsemiconductor materials (e.g., conductively-doped silicon,conductively-doped germanium, etc.). In some embodiments, the conductivematerial 20 may comprise tungsten, either alone or in combination withone or more suitable conductive barrier materials (e.g.,oxidation-resistant materials which protect the tungsten from oxidationin embodiments in which the tungsten may be exposed to oxygen).

The conductive lines 18 may be formed to any suitable thickness, and insome embodiments may be formed to a thickness of at least about 20nanometers (nm). The conductive lines may be formed to any suitablepitch; and in some embodiments may be formed to a pitch within a rangeof from about 20 nm to about 100 nm (e.g., a pitch about 40 nm).

The conductive lines may be formed with any suitable processing. Forinstance, a film of conductive material 20 may be formed over an uppersurface of the mass 12, a patterned mask (not shown) may be formed overthe film to define locations of the lines 18, and a pattern may betransferred from the mask into the film to form the lines 18. The maskmay be removed to leave the conductive lines 18, or in some embodimentsat least a portion of the mask may remain as part of the assembly 10 atthe process stage of FIG. 2.

The conductive lines 18 are spaced from one another by gaps 22. Suchgaps are extended into the mass 12 of the semiconductor material 14 toform trenches 24. The trenches 24 may be formed to any suitable depth;such as, for example, a depth within a range of from about 150 nm toabout 300 nm (e.g., a depth of about 180 nm).

The trenches 24 extend along a first direction represented by an axis 5.The trenches 24 may be referred to as first trenches to distinguish themfrom other trenches formed at subsequent process stages.

The trenches 24 have sidewalls 25 and have bottom peripheries 27. Insome embodiments, the trenches 24 may be considered to formsemiconductor material walls 26 from the semiconductor material 14, andthe sidewalls 25 may be considered to be along surfaces of suchsemiconductor material walls.

The bottom peripheries 27 of the trenches 24 are over a remaining base28 of the semiconductor material 14.

Referring to FIG. 3, an insulative mass 30 is formed to fill thetrenches 24 and to cover the conductive lines 18. The insulative mass 30is shown to comprise two insulative compositions 32 and 34, with thelower insulative composition 32 filling the trenches 24, and the upperinsulative composition 34 being over the lower insulative composition32. In some embodiments, the insulative compositions 32 and 34 may bothcomprise a same composition as one another; and may, for example, bothcomprise, consist essentially of, or consist of silicon dioxide. Inother embodiments, the insulative compositions 32 and 34 may comprisedifferent compositions relative to one another. In some embodiments, theinsulative compositions 32 and 34 may both comprise silicon dioxide, butone of the compositions may have a different density than the other ofthe compositions.

In some embodiments, the insulative composition 34 may be considered tobe a dielectric bonding material. The dielectric bonding material 34 hasan upper surface 31. The upper surface 31 may be a planarized surfaceformed utilizing a suitable polishing process; such as, for example,chemical-mechanical polishing (CMP). The dielectric bonding material 34may be referred to as a first dielectric bonding material to distinguishit from other dielectric bonding materials formed at later processstages.

In some embodiments, the semiconductor material 14, conductive lines 18,and insulative mass 30 may be considered together to form a firstassembly 36.

Referring to FIG. 4, the first assembly 36 is inverted and bonded to asecond assembly 40. The second assembly 40 includes a dielectric bondingmaterial 42 over a semiconductor material 38. In some embodiments, thedielectric bonding material 42 may be referred to as a second dielectricbonding material to distinguish it from the first dielectric bondingmaterial 34.

In some embodiments, the semiconductor material 38 may be referred to asa second semiconductor material to distinguish it from the firstsemiconductor material 14. The second semiconductor material 38 maycomprise any of the semiconductor compositions described above relativeto the first semiconductor material 14. The second semiconductormaterial 38 may comprise a same composition as the first semiconductormaterial 14, or may comprise a different composition relative to thefirst semiconductor material 14. In some embodiments, the first andsecond semiconductor materials 14 and 38 may both comprise, consistessentially of, or consist of monocrystalline silicon.

The second dielectric bonding material 42 has an upper surface 37. Thesurface 31 of the first dielectric bonding material 34 is bonded to thesurface 37 of the second dielectric bonding material 42 to form adielectric bonding region 44. The bonded assemblies 36 and 40 may beconsidered together to form a third assembly 46.

An upper surface of the third assembly 46 would initially comprise thebase 28 (shown as the bottom of the first assembly 36 at the processingstage of FIG. 3), but such base is removed with an appropriate polishingprocess (e.g., CMP) to form the planarized upper surface 47 of the thirdassembly 46 at the processing stage of FIG. 4.

The insulative material 32 within trenches 24 (with the trenches 24being labeled in FIG. 2) forms insulative walls 48 at the processingstage of FIG. 4. Such insulative walls alternate with the semiconductormaterial walls 26. The planarized surface 47 extends across theinsulative walls 48 and the semiconductor material walls 26.

The construction 10 of FIG. 4 may be considered to be an integratedarrangement which includes all of the materials and structures of thethird assembly 46.

The semiconductor material walls 26 and insulative walls 48 extend alongthe first direction of axis 5, and alternate with one another along asecond direction represented by an axis 7.

Referring to FIG. 5, masking material 50 is formed over the planarizedupper surface 47 (labeled in FIG. 4), and patterned into a plurality oflines 52. The lines 52 extend along the second direction of axis 7. Thesecond direction of axis 7 intersects the first direction of axis 5. Inthe illustrated embodiment, the second direction of axis 7 issubstantially orthogonal to the first direction of axis 5; with the term“substantially orthogonal” meaning orthogonal to within reasonabletolerances of fabrication and measurement.

The masking material 50 may comprise any suitable composition orcombination of compositions; and in some embodiments may comprise,consist essentially of, or consist of silicon nitride. The maskingmaterial 50 may be patterned into the illustrated lines 52 utilizing anysuitable methodology. For instance, in some embodiments alithographically-patterned mask (not shown) may be utilized to definelocations of the lines 52, and a pattern may be transferred from suchmask to the masking material 50 utilizing one or more suitable etches.The mask may be removed to leave the configuration shown in FIG. 5, orin other embodiments may remain at the process stage of FIG. 5.

The lines 52 are utilized to pattern trenches 54 which extend along thesecond direction of axis 7. The trenches 54 extend downwardly into thesemiconductor walls 26 (the walls 26 are labeled in FIG. 4), and formsemiconductor material pillars 56 from upper regions of the secondmaterial walls. Lower regions of the semiconductor material walls becomerails 60; with such rails extending along the conductive lines 18, andextending along the first direction of axis 5.

The trenches 54 are formed with etching which removes the semiconductormaterial 14 faster than the insulative material 32. Accordingly, suchetching leaves steps 58 of the insulative material 32 along bottomperipheries of the trenches 54. In the illustrated embodiment, thebottom peripheries of the trenches 54 have upper surfaces 59 over theinsulative steps 58, and have lower surfaces 61 over the semiconductormaterial rails 60. Accordingly, the bottom peripheries of the trenches54 have undulating topographies which include higher regions along topedges of the steps 58 (with the top edges of the steps corresponding tothe surfaces 59), and which include lower regions along the top edges ofthe semiconductor material rails 60 (with the top edges of the railscorresponding to the surfaces 61). In the shown embodiment, thesemiconductor material rails 60 only include n-type doped material ofthe n-type doped region 16.

The trenches may have any suitable dimensions; and in some embodimentsmay have depths within a range of from about 50 nm to about 150 nm(e.g., about 100 nm) over the steps 58; and may have depths within arange of from about 100 nm to about 200 nm (e.g., about 150 nm) over theupper surfaces 61 of the semiconductor material rails 60.

The semiconductor material pillars 56 have sidewall edges 63 exposedwithin the trenches 54, and the semiconductor material rails 60 have thetop edges 61 exposed within such trenches.

Referring to FIG. 6, dielectric material 62 is formed along the sidewalledges 63 of the semiconductor material pillars 56, and along the topedges 61 of the semiconductor material rails 60. The dielectric material62 may comprise any suitable composition or combination of compositions;and in some embodiments may comprise, consist essentially of, or consistof silicon dioxide.

The dielectric material 62 may be formed with any suitable methodology.For instance, in embodiments in which the semiconductor material 14comprises monocrystalline silicon, the dielectric material 62 maycomprise silicon dioxide formed by oxidation of the monocrystallinesilicon along exposed surfaces of the semiconductor material pillars 56and the semiconductor material rails 60. Such oxidation may beaccomplished with any suitable methodology; including, for example, lampannealing.

The dielectric material 62 may have any suitable thickness; and in someembodiments may have a thickness within a range of from about 1 nm toabout 6 nm (e.g., a thickness of about 4 nm).

In some embodiments, the dielectric material 62 may be referred to asgate dielectric.

Referring to FIG. 7, conductive material 64 is formed within thetrenches 54 and adjacent the dielectric material 62. The conductivematerial 64 may comprise any suitable electrically conductivecomposition(s); such as, for example, one or more of various metals(e.g., titanium, tungsten, cobalt, nickel, platinum, ruthenium, etc.),metal-containing compositions (e.g., metal silicide, metal nitride,metal carbide, etc.), and/or conductively-doped semiconductor materials(e.g., conductively-doped silicon, conductively-doped germanium, etc.).In some embodiments, the conductive material 64 may comprise, consistessentially of, or consist of titanium nitride.

The conductive material 64 is etched back within the trenches 54 toleave openings 68 over the conductive material 64. The openings 68 mayhave any suitable depths; and in some embodiments may have depths withina range of from about 30 nm to about 80 nm (e.g., about 50 nm).

The conductive material 64 forms conductive lines 66 within the trenches54, and such conductive lines extend along the second direction of axis7. The conductive lines 66 may be referred to as second conductive linesto distinguish them from the first conductive lines 18. In someembodiments, the second conductive lines 66 may correspond to wordlines.

Referring to FIG. 8, insulative material 70 is formed within theopenings 68 (labeled in FIG. 7); and then polishing (e.g., CMP) isutilized to remove material 50 (shown in FIG. 7) and form a planarizedupper surface 71. Upper regions of the semiconductor material pillars 56are exposed along the planarized upper surface 71. Such upper regionsare doped to form n-type doped regions 72. The doping may beaccomplished utilizing any suitable processing; including, for example,implanting of appropriate dopant into the semiconductor material 14 ofthe semiconductor material pillars 56.

The semiconductor material pillars 56 become active regions of verticaltransistors 74. The n-type doped regions 16 and 72 correspond tosource/drain regions of the vertical transistors 74, and the p-typedoped regions 17 correspond to channel regions of such verticaltransistors. The wordlines 66 comprise gates which gatedly couple thesource/drain regions 16 and 72 to one another through the channelregions 17. Although the source/regions 16/72 are shown to be n-typedoped, and the channel regions 17 to be p-type doped, in otherembodiments the source/drain regions 16/72 may be p-type doped and thechannel regions may be n-type doped.

The insulative material 70 may comprise any suitable composition(s); andin some embodiments may comprise, consist essentially of, or consist ofsilicon nitride.

Referring to FIG. 9, memory structures 76 are formed over thesemiconductor material pillars 56. Each of the memory structures 76forms a memory cell. The memory structures 76 may be configured forutilization in resistive RAM cells, MRAM cells, STT-MRAM cells, etc. Forinstance, in some embodiments the memory structures 76 may comprisepinned magnetic layers, free magnetic layers, and tunnel barrier layersbetween the pinned and free magnetic layers; and accordingly maycomprise magnetic tunnel junctions (MTJs) of the type utilized in MRAMcells, (for example, STT-MRAM cells).

Referring to FIG. 10, insulative material 78 is formed between thememory structures 76. The insulative material 78 may comprise anysuitable composition(s); and in some embodiments may comprise, consistessentially of, or consist of silicon nitride. The insulative material78 may comprise a same composition as the underlying insulative material70 in some embodiments, and in other embodiments may comprise adifferent composition relative to the insulative material 70.

Conductive material 80 is formed over the memory structures 76, and ispatterned into conductive lines 82. The conductive material 80 maycomprise any suitable electrically conductive composition(s), such as,for example, one or more of various metals (e.g., titanium, tungsten,cobalt, nickel, platinum, ruthenium, etc.), metal-containingcompositions (e.g., metal silicide, metal nitride, metal carbide, etc.),and/or conductively-doped semiconductor materials (e.g.,conductively-doped silicon, conductively-doped germanium, etc.). In someembodiments, the conductive material 80 may comprise, consistessentially of, or consist of tungsten. The conductive material 80 maybe formed to any suitable thickness, and in some embodiments may beformed to a thickness within a range of from about 10 nm to about 50 nm(e.g., about 20 nm).

The conductive lines 82 extend along the first direction of the axis 5.

In some embodiments, the conductive lines 82 may be referred to as thirdconductive lines to distinguish them from the first conductive lines 18and the second conductive lines 66.

In some embodiments, the memory structures 76 correspond to MRAM cells(e.g. STT-MRAM cells) of a memory array 84. The first conductive lines18 are bitlines or source lines associated with such memory array; thethird conductive lines 82 are the other of bitlines and source linesassociated with the memory array; and the second conductive lines 66 arewordlines associated with the memory array. Each individual memorystructure is uniquely addressed through a combination comprising one ofthe first conductive lines 18, one of the second conductive lines 66,and one of the third conductive lines 82. An example memory array isdescribed in more detail below with reference to FIG. 15.

An advantage of the processing of FIGS. 1-10 is that such may enablevertical access transistors to be formed which have single crystalsemiconductor material (e.g., single crystal silicon) throughout activeregions (i.e., source/drain regions and channel regions) of the accesstransistors. Such may enable improved scalability of the vertical accesstransistors to higher levels of integration than may be achieved withvertical access transistors having polycrystalline semiconductormaterial throughout the active regions of the access transistors.

Referring to FIG. 11, relevant electrical components of the memory array84 are shown in isolation from some of the insulative materials in orderto assist the reader in understanding the invention. The figure showsthat the memory array 84 comprises a plurality of vertical accesstransistors 74 configured as access devices for the memory structures76. Each vertical access transistor is between a pair of wordlines 66,and the wordlines are shared between neighboring vertical accesstransistors during operation of the memory array 84.

FIG. 12 is a cross-sectional side view along a region of the memoryarray 84. One of the first conductive lines 18 is labeled as a bitline(BL) and one of the third conductive lines 82 is labeled as a sourceline (SL). Five neighboring access transistors 74 are shown in thecross-section of FIG. 12. Four wordlines 66 are shown associated withthe access transistors. Three of the access transistors are labeled as(a), (b) and (c). The “ON” and “OFF” states of the wordlines 66 aredescribed, with such states being configured to place the accesstransistor (a) in a fully ON mode, to place the access transistor (c) ina fully OFF mode, and to place the access transistor (b) in a HALF-ON(i.e., SEMI-ON) mode.

FIG. 13 graphically illustrates current and voltage characteristics ofthe various modes of the access transistors (a), (b) and (c) of FIG. 12.The HALF-ON mode (b) has a substantially smaller current value then theON mode (a), and accordingly may be readily distinguished from the ONmode so that the HALF-ON mode does not adversely impact reading/writingoperations.

Referring to FIG. 14, a peripheral circuit element 86 is shown providedproximate the memory array 84. The circuit element 86 may correspond toa switching element.

The circuit element 86 has a conductive interconnect 88 which extends toa wordline driver (labeled as “Driver”). The interconnect 88 iselectrically coupled with a source/drain region 90. Such source/drainregion is gatedly coupled with another source/drain region 92 through achannel region 94. The channel region is gatedly controlled through gateelectrodes 96.

The source/drain region 92 is over a conductive beam 98 (e.g., atungsten-containing beam); and is electrically coupled with a pair ofconductive beams 100 and 102. The conductive beams 100 and 102 extend toa pair of neighboring wordlines 66 within the memory array 84. Inoperation, the switching element 86 may be utilized to simultaneouslydrive the illustrated two neighboring wordlines 66 within the memoryarray 84. For instance, ON electrical signals may be applied alonginterconnect 88 and along the gate electrodes 96, and such may result inthe ON electrical state being provided along both of the conductivebeams 100 and 102 to simultaneously provide the ON voltage along both ofthe illustrated neighboring wordlines 66.

FIG. 15 shows a region of an example memory array 84, and shows exampleregions of example peripheral circuitries 114 and 116 adjacent thememory array 84. The memory array comprises a plurality of memory cells76 (MC) and access transistors 74. Wordlines (WLn, WLn+1, etc.) arecoupled with gates of the access transistors, and extend to wordlinedriver circuitries. In the shown embodiment, there are two wordlinedriver circuitries, which are labeled as Row Decoder/Driver #1 and RowDecoder/Driver #2. The wordline driver circuitries may be referred to asa first wordline driver circuitry and a second wordline drivercircuitry, respectively.

Source lines (SLm, SLm+1, etc.) are coupled with the memory cells MC,and bitlines (BLm, BLm+1, etc.) are coupled with the access transistors74. The source lines and bitlines extend to sense circuitry, columndecoder circuitry, and column driver circuitry (labeled as Sense CKT &Column Decoder/Driver).

Each of the memory cells MC is uniquely addressed through a combinationcomprising one of the source lines, one of the bitlines and one of thewordlines.

In some embodiments, the wordlines (WLn, WLn+1, etc.) may be consideredto comprise a set of even wordlines (E) and odd wordlines (O); with theterms “even” and “odd” being utilized to enable one set of wordlines tobe distinguished relative to another set, and are not to be understoodas indicating any substantial structural differences between thewordlines. The even and odd wordlines alternate with one another acrossthe memory array 84.

The access transistors 74 are arranged in rows (Rn, Rn+1, etc.) acrossthe memory array 84, with each row being between an even wordline (E)and an odd wordline (O). The access transistors comprise thesemiconductor material pillars 56 (as shown in FIG. 11), and accordinglythe semiconductor material pillars 56 would also be arranged in the samerows as the access transistors 74.

The rows may be considered to alternate between first rows (F) andsecond rows (S). Each of the rows (F and S) is associated with one ofthe even wordlines (E) and one of the odd wordlines (O). The even andodd wordlines (E and O) associated with each of the first rows (F)extend to first common lines 110, which in turn extend to the firstwordline driver circuitry (Row Decoder/Driver #1); and the even and oddwordlines (E and O) associated with each of the second rows (S) extendto second common lines 112, which in turn extend to the second wordlinedriver circuitry (Row Decoder/Driver #2).

In some embodiments, FIGS. 1-15 may be considered to describe a firstexample method of forming vertical access transistors. Another examplemethod is described with reference to FIGS. 16-29.

Referring to FIG. 16, a construction 10 a includes a mass 12 of thefirst semiconductor material 14.

Referring to FIG. 17, masking material 200 is formed over an uppersurface of the mass 12, and is patterned into lines 202. The lines 202extend along the second direction of the axis 7.

The masking material 200 may comprise any suitable composition(s); andin some embodiments may comprise, consist essentially of, or consist ofsilicon nitride. The masking material may be formed to any suitablethickness, and in some embodiments may be formed to a thickness within arange of from about 10 nm to about 50 nm (e.g., about 30 nm). The lines202 may be formed on any suitable pitch; and in some embodiments may beformed to a pitch within a range of from about 20 nm to about 100 nm(e.g., a pitch about 40 nm). The lines 202 may be formed with anysuitable process; and in some embodiments may be formed utilizing alithographically-patterned mask (not shown).

The lines 202 are utilized to pattern trenches 204 which extend into thesemiconductor material 14. A portion of the semiconductor material 14remaining under the trenches 204 may be considered to be a base 208, andportions of the semiconductor material 14 between the trenches 204 maybe considered to be configured as semiconductor material walls 206. Thetrenches 204 may be referred to as first trenches to distinguish themfrom other trenches formed at subsequent process stages.

The trenches 204 may be formed with any suitable etching; such as, forexample, dry etching.

The trenches 204 have sidewalls 205, and such sidewalls may beconsidered to be along the semiconductor material walls 206.

The trenches 204 have bottom peripheries 207, and such bottomperipheries may be considered to be over the base 208.

Referring to FIG. 18, the sidewalls 205 and bottom peripheries 207 ofthe trenches 204 are lined with dielectric material 62. Insulative steps210 are then formed within bottom regions (i.e., along bottoms) of thetrenches 204. The insulative steps comprise insulative material 212.

The insulative material 212 may comprise any suitable composition(s);and in some embodiments may comprise, consist essentially of, or consistof silicon dioxide. In some embodiments, the insulative steps may beformed by forming the material 212 within the trenches 204 utilizing aspin-coating method, followed by appropriate etching (e.g., wet etching)to recess the material 212 within the trenches. In some embodiments, thetrenches 204 may be formed to depths within a range of from about 100 nmto about 300 nm (e.g., about 200 nm), and the steps 210 may be formed toa suitable thickness is such that the remaining portion of the trenchhas a depth within a range of from about 80 nm to about 200 nm (e.g.,about 160 nm).

Conductive material 214 is formed within the trenches 204 and over theinsulative steps 210. The conductive material 214 may comprise anysuitable electrically conductive composition(s); such as, for example,one or more of various metals (e.g., titanium, tungsten, cobalt, nickel,platinum, ruthenium, etc.), metal-containing compositions (e.g., metalsilicide, metal nitride, metal carbide, etc.), and/or conductively-dopedsemiconductor materials (e.g., conductively-doped silicon,conductively-doped germanium, etc.). In some embodiments, the conductivematerial 214 may comprise, consist essentially of, or consist oftitanium nitride.

The conductive material 214 may be formed to any suitable thickness; andin some embodiments may comprise a thickness within a range of fromabout 2 nm to about 10 nm (e.g., about 4 nm).

The conductive material 214 is configured as conductive beams 216 whichextend along the second direction of the axis 7. Each of the conductivebeams 216 is configured as an upwardly-opening container shape.Specifically, each of the beams 216 comprises a pair of sidewall regions218 joined to one another through an interconnect region 220.

The conductive beams 216 are recessed within the trenches 204. Suchrecessing may be accomplished with any suitable processing. Suitableprocessing will be readily recognized by persons of ordinary skill inthe art.

Referring to FIG. 19, insulative material 222 is formed within thetrenches 204 (labeled in FIG. 18) and over the conductive beams 216. Theinsulative material 222 may be considered to form insulative regions224. The insulative material 222 may comprise any suitablecomposition(s); and in some embodiments may comprise, consistessentially of, or consist of silicon nitride.

N-type region 16 and p-type region 17 are formed within thesemiconductor material 14 utilizing suitable processing (e.g.,appropriate implanting). In other embodiments, the regions 16 and 17 maycorrespond to a p-type region and an n-type region, respectively. Insome embodiments, the regions 16 and 17 may be formed at a processingstage other than that of FIG. 19. For instance, in some embodiments theregions 16 and 17 may be present at the processing stage of FIG. 16.

A planarized surface 225 is formed across the materials 14, 62 and 222of construction 10 a. Such planarized surface may be formed utilizingany suitable processing; such as, for example, CMP.

Referring to FIG. 20, conductive material 226 is formed over theplanarized surface 225 (FIG. 19) and patterned into lines 228. The lines228 may be formed with any suitable processing, including, for example,utilization of a lithographically-patterned mask (not shown).

The conductive material 226 may comprise any suitable electricallyconductive composition(s); such as, for example, one or more of variousmetals (e.g., titanium, tungsten, cobalt, nickel, platinum, ruthenium,etc.), metal-containing compositions (e.g., metal silicide, metalnitride, metal carbide, etc.), and/or conductively-doped semiconductormaterials (e.g., conductively-doped silicon, conductively-dopedgermanium, etc.). In some embodiments, the conductive material 226 maycomprise, consist essentially of, or consist of tungsten. The tungstenmay be formed to any suitable thickness; such as, for example, athickness of from about 10 nm to about 50 nm (e.g. about 20 nm).

In some embodiments, the lines 228 may be referred to as firstconductive lines to distinguish them from other conductive lines.

The conductive lines 228 extend along the first direction of the axis 5.In the shown embodiment, the lines 228 extends across the insulativeregions 224 and the semiconductor material walls 206.

The conductive lines 228 are utilized to pattern second trenches 230.The second trenches 230 are formed between the conductive lines 228, andextend into the semiconductor material walls 206 to a level which isabove a top level of the upwardly-opening container-shaped conductivebeams 216. The second trenches 230 extend into, but not through, then-type doped regions 16.

In some embodiments, the semiconductor material 14 and other associatedmaterials and structures of the construction 10 a at the process stageof FIG. 20 may be considered together to form a first assembly 252.

Referring to FIG. 21, an insulative mass 256 is formed within the secondtrenches 230 (FIG. 20) and over the conductive lines 228, and then thefirst assembly 252 is inverted. The insulative mass 256 comprisesinsulative material 254. The insulative material 254 may comprise anysuitable composition(s); and in some embodiments may comprise, consistessentially of, or consist of silicon dioxide.

In some embodiments, the insulative material 254 may be considered to bea dielectric bonding material. The dielectric bonding material 254 has asurface 255. The dielectric bonding material 254 may be referred to as afirst dielectric bonding material.

The inverted first assembly 252 is bonded to a second assembly 258. Thesecond assembly 258 includes a dielectric bonding material 260 over asemiconductor material 262. In some embodiments, the dielectric bondingmaterial 260 may be referred to as a second dielectric bonding materialto distinguish it from the first dielectric bonding material 254. Insome embodiments, the semiconductor material 262 may be referred to as asecond semiconductor material to distinguish it from the firstsemiconductor material 14.

The second semiconductor material 262 may comprise any of thesemiconductor compositions described above relative to the firstsemiconductor material 14. The second semiconductor material 262 maycomprise a same composition as the first semiconductor material 14, ormay comprise a different composition relative to the first semiconductormaterial 14. In some embodiments, the first and second semiconductormaterials 14 and 262 may both comprise, consist essentially of, orconsist of monocrystalline silicon.

The second dielectric bonding material 260 has a surface 261. Thesurface 255 of the first dielectric bonding material 254 is bonded tothe surface 261 of the second dielectric bonding material 260 to form adielectric bonding region 264. The bonded assemblies 252 and 258 may beconsidered together to form a third assembly 266.

An upper surface of the third assembly 266 would initially comprise thebase 208 (shown at the bottom of the first assembly 252 at theprocessing stage of FIG. 20), but such base is removed with anappropriate polishing process (e.g., CMP) to form a planarized uppersurface 267 of the third assembly 266 at the processing stage of FIG.21. The planarized upper surface 267 extends across the insulativematerial 212 of steps 210, across the dielectric material 62, and acrossthe semiconductor material walls 206.

The construction 10 a of FIG. 21 may be considered to be an integratedarrangement which includes all of the materials and structures of thethird assembly 266.

It is noted that the conductive beams 216 of assembly 266 of FIG. 21 arenow configured as downwardly-opening container shapes. Each of thedownwardly-opening container shapes comprises the pair of sidewallregions 218, and comprises the interconnect region 220 as a top regionextending across the sidewall regions.

The assembly 266 may be considered to have the first conductive lines228 over the dielectric bonding region 264. The conductive lines 228extend along the first direction of axis 5. The conductive beams 216 areover the conductive lines 228, and are spaced from one another by thesemiconductor material walls 206 and the dielectric material 62. Thesemiconductor material walls 206 and the conductive beams 216 extendalong the second direction of axis 7. The second direction of axis 7intersects the first direction of axis 5; and in some embodiments may besubstantially orthogonal to the first direction of axis 5.

The conductive beams 216 and the semiconductor material walls 206alternate with one another along the first direction of axis 5.

The semiconductor material walls 206 have bottom surfaces 269. Suchbottom surface undulate over top surfaces 271 of the conductive lines228, and top surfaces 273 of the insulative material 254. In someembodiments, the bottom surfaces 269 of the semiconductor material walls206 may be considered to have first regions 270 over the upper surfaces271 of the conductive lines 228, and to have second regions 272 over theupper surfaces 273 of insulative material 254; with the second regions272 being higher than the first regions 270.

Referring to FIG. 22, masking material 274 is formed over the planarizedsurface 267 (shown in FIG. 21) and is patterned into lines 276. Themasking material 274 may comprise any suitable composition(s); and insome embodiments may comprise, consist essentially of, or consist ofsilicon nitride. The masking material 274 may have any suitablethickness; and in some embodiments may have a thickness within a rangeof from about 10 nm to about 60 nm (e.g., about 30 nm). The lines 276may be formed on any suitable pitch; and in some embodiments may beformed to a pitch within a range of from about 20 nm to about 60 nm(e.g., about 40 nm). The lines 276 may be formed with any suitableprocess; and in some embodiments may be formed by transferring a patternfrom a lithographically-patterned mask (not shown).

The lines 276 are spaced from one another by openings (i.e., gaps) 278.Etching (e.g., dry etching) is conducted to remove portions of thesemiconductor material walls 206 (labeled in FIG. 21) exposed within theopenings 278. The semiconductor material 14 of the semiconductormaterial walls 206 is removed selectively relative to other materialsexposed within the openings 278. In other words, regions of the openings278 are extended downwardly through the semiconductor material walls.Such forms semiconductor material pillars 280 from the semiconductormaterial walls 206 (i.e., such patterns the semiconductor material walls206 into semiconductor material pillars 280). The semiconductor materialpillars 280 extend upwardly from the upper surfaces 271 of theconductive lines 228; and accordingly comprise the first regions 270 ofthe bottom surfaces of the walls 206 (with such first regions havingbeen described above with reference to FIG. 21).

The openings 278 extend downwardly to the upper surfaces 273 of theinsulative material 254.

Referring to FIG. 23, the openings 278 (shown in FIG. 22) are filledwith insulative material 282. The insulative material 282 may compriseany suitable composition(s); and in some embodiments may comprise,consist essentially of, or consist of silicon nitride.

After the openings 278 are filled with the insulative material 282,polishing (e.g., CMP) is conducted to remove the masking material 274(shown in FIG. 22). The polishing forms a planarized upper surface 283extending across the semiconductor material 14, conductive material 214,dielectric material 62 and insulative material 282. The polishingremoves portions of the conductive beams 216 (shown in FIG. 22). Thepolishing specifically removes the top regions 220 (shown in FIG. 22) ofsuch conductive beams; and thereby forms spaced-apart conductive lines284 from remaining portions of the sidewall regions 218 of theconductive beams 216 (shown in FIG. 22).

The conductive lines 284 extend along the second direction of axis 7.The conductive lines 284 may be referred to as second conductive linesto distinguish them from the first conductive lines 228.

Upper regions of the semiconductor material pillars 280 are doped withn-type dopant to form the n-type doped regions 72. Such doping they beaccomplished with any suitable processing; such as, for example, asuitable implant.

Referring to FIG. 24, upper surfaces of the conductive lines 284 arerecessed relative to the planarized surface 283. Such recessing may beaccomplished utilizing any suitable processing; such as, for example, awet etch selective for the conductive material 214 relative to thematerials 62, 282 and 14.

Referring to FIG. 25, insulative material 288 is formed over therecessed lines 284, and patterned insulative material 290 is formed overthe upper surface 283 (FIG. 24). The insulative materials 288 and 290may comprise any suitable composition(s); including, for example, one orboth of silicon nitride and silicon dioxide. For instance, material 288may comprise silicon nitride while material 290 comprises silicondioxide.

The patterned insulative material 290 has openings 292 extendingtherethrough to expose upper surfaces of the semiconductor materialpillars 280. Memory structures 294 are formed within such openings.

The memory structures 294 may be configured for utilization in resistiveRAM cells, MRAM cells, STT-MRAM cells, etc. For instance, in someembodiments the memory structures 294 may comprise pinned magneticlayers, free magnetic layers, and tunnel barrier layers between thepinned and free magnetic layers; and accordingly may comprise magnetictunnel junctions (MTJs) of the type utilized in MRAM cells, (e.g.,STT-MRAM cells).

Referring to FIG. 26, conductive material 300 is formed over the memorystructures 294 and is patterned into conductive lines 302. Theconductive material 300 may comprise any suitable electricallyconductive composition(s); such as, for example, one or more of variousmetals (e.g., titanium, tungsten, cobalt, nickel, platinum, ruthenium,etc.), metal-containing compositions (e.g., metal silicide, metalnitride, metal carbide, etc.), and/or conductively-doped semiconductormaterials (e.g., conductively-doped silicon, conductively-dopedgermanium, etc.). In some embodiments, the conductive material 300 maycomprise, consist essentially of, or consist of tungsten. The conductivematerial 300 may be formed to any suitable thickness, and in someembodiments may be formed to a thickness within a range of from about 10nm to about 50 nm (e.g., about 20 nm).

The conductive lines 302 extend along the first direction of the axis 5.

In some embodiments, the conductive lines 302 may be referred to asthird conductive lines to distinguish them from the first conductivelines 228 and the second conductive lines 284.

Each of the memory structures 294 forms a memory cell. In someembodiments, the memory cells 294 correspond to MRAM cells (e.g.STT-MRAM cells) of a memory array 304. The first conductive lines 228are bitlines or source lines associated with such memory array; thethird conductive lines 302 are the other of bitlines and source linesassociated with the memory array; and the second conductive lines 284are wordline components associated with the memory array. The wordlinecomponents on each side of a semiconductor pillar are paired with oneanother to form a wordline (shown as wordlines WL1, WL2 and WL3; withonly one of the wordline components of WL3 being shown in FIG. 26). Eachindividual memory structure 294 is uniquely addressed through acombination comprising one of the first conductive lines 228, a pair ofthe second conductive lines 284 (e.g., one of the wordlines WL1, WL2 andWL3), and one of the third conductive lines 302. An example memory arrayis described in more detail below with reference to FIG. 29.

An advantage of the processing of FIGS. 16-26 is that such may enablevertical access transistors to be formed which have single crystalsilicon material (e.g., single crystal silicon) throughout source/drainregions and channel regions of the access transistors. Such may enableimproved scalability of the access transistors to higher levels ofintegration than may be achieved with vertical access transistors havingpolycrystalline semiconductor material throughout the source/drainregions and channel regions.

Referring to FIG. 27, relevant electrical components of the memory array304 are shown in isolation from some of the insulative materials inorder to assist the reader in understanding the invention. The figureshows that the memory array 304 comprises a plurality of verticaltransistors 74 configured as access devices for the memory structures294. Each vertical transistor is between a pair of wordline components284, and the paired wordline components together form wordlines (e.g.,WL1, WL2 and WL3; with only one of the wordline components of WL3 beingshown in FIG. 27).

The memory array 304 of FIG. 27 is an example application for thevertical access transistors 74. However, it is to be understood that thevertical access transistors may be utilized in other applications. Forinstance, FIG. 28 shows an alternative memory array 314 which utilizescapacitors 310 (or other suitable charge-storage devices) as memorystructures of memory cells. In some applications, the memory array 314and may be a DRAM array having memory cells comprising the capacitors310.

FIG. 29 shows a region of an example memory array 304 of the typedescribed in FIGS. 26 and 27, and shows example regions of exampleperipheral circuitries 414 and 416 adjacent the memory array 304. Thememory array comprises a plurality of memory cells 294 (MC) and accesstransistors 74. Wordlines (WLn, WLn+1, etc.) are coupled with gates ofthe access transistors, and extend to wordline driver circuitry (labeledas Row Decoder/Driver). Each wordline comprises a first component (e.g.,WLn(E)) and a second component (e.g., WLn(O)). The first components maybe referred to as even components, and the second components may bereferred to as odd components. The terms “even” and “odd” are utilizedto enable one set of wordline components to be distinguished relative toanother set, and do not indicate any substantial structural differencebetween the wordline components. The even and odd wordline componentsalternate with one another across the memory array 304.

Source lines (SLm, SLm+1, etc.) are coupled with the memory cells MC,and bitlines (BLm, BLm+1, etc.) are coupled with the access transistors74. The source lines and bitlines extend to sense circuitry, columndecoder circuitry, and column driver circuitry (labeled as Sense CKT &Column Decoder/Driver).

Each of the memory cells MC is uniquely addressed through a combinationcomprising one of the source lines, one of the bitlines and one of thewordlines.

The access transistors 74 are arranged in rows (Rn, Rn+1, etc.) acrossthe memory array 304, with each row being between one of the evenwordline components and one of the odd wordline components. The accesstransistors comprise the semiconductor material pillars 280 (as shown inFIGS. 26 and 27), and accordingly the semiconductor material pillars 280would also be arranged in the same rows as the access transistors 74.

The assemblies and structures discussed above may be utilized withinintegrated circuits (with the term “integrated circuit” meaning anelectronic circuit supported by a semiconductor substrate); and may beincorporated into electronic systems. Such electronic systems may beused in, for example, memory modules, device drivers, power modules,communication modems, processor modules, and application-specificmodules, and may include multilayer, multichip modules. The electronicsystems may be any of a broad range of systems, such as, for example,cameras, wireless devices, displays, chip sets, set top boxes, games,lighting, vehicles, clocks, televisions, cell phones, personalcomputers, automobiles, industrial control systems, aircraft, etc.

Unless specified otherwise, the various materials, substances,compositions, etc. described herein may be formed with any suitablemethodologies, either now known or yet to be developed, including, forexample, atomic layer deposition (ALD), chemical vapor deposition (CVD),physical vapor deposition (PVD), etc.

The terms “dielectric” and “insulative” may be utilized to describematerials having insulative electrical properties. The terms areconsidered synonymous in this disclosure. The utilization of the term“dielectric” in some instances, and the term “insulative” (or“electrically insulative”) in other instances, may be to providelanguage variation within this disclosure to simplify antecedent basiswithin the claims that follow, and is not utilized to indicate anysignificant chemical or electrical differences.

The particular orientation of the various embodiments in the drawings isfor illustrative purposes only, and the embodiments may be rotatedrelative to the shown orientations in some applications. Thedescriptions provided herein, and the claims that follow, pertain to anystructures that have the described relationships between variousfeatures, regardless of whether the structures are in the particularorientation of the drawings, or are rotated relative to suchorientation.

The cross-sectional views of the accompanying illustrations only showfeatures within the planes of the cross-sections, and do not showmaterials behind the planes of the cross-sections, unless indicatedotherwise, in order to simplify the drawings.

When a structure is referred to above as being “on”, “adjacent” or“against” another structure, it can be directly on the other structureor intervening structures may also be present. In contrast, when astructure is referred to as being “directly on”, “directly adjacent” or“directly against” another structure, there are no interveningstructures present.

Structures (e.g., layers, materials, etc.) may be referred to as“extending vertically” to indicate that the structures generally extendupwardly from an underlying base (e.g., substrate). Thevertically-extending structures may extend substantially orthogonallyrelative to an upper surface of the base, or not.

Some embodiments include a method of forming integrated circuitry. Astructure is formed which has first conductive lines over a dielectricbonding region, has semiconductor material pillars extending upwardlyfrom the first conductive lines, and has second conductive lines overthe first conductive lines and extending along sidewalls of thesemiconductor material pillars. The first conductive lines extend alonga first direction, and the second conductive lines extend along a seconddirection which intersects the first direction. The semiconductormaterial pillars include a first semiconductor material. The structureincludes a second semiconductor material under the dielectric bondingregion. The first semiconductor material is monocrystalline silicon.Memory structures are formed over the semiconductor material pillars.The memory structures are within a memory array. Third conductive linesare formed over the memory structures. The third conductive lines extendalong the first direction. Individual memory structures of the memoryarray are uniquely addressed through combinations of the first, secondand third conductive lines.

Some embodiments include a method of forming integrated circuitry. Astructure is formed which has first conductive lines over a dielectricbonding region, has semiconductor material walls over the firstconductive lines, and has insulative walls between the semiconductormaterial walls. The first conductive lines, the insulative walls, andthe semiconductor material walls all extend along a first direction. Theinsulative walls and the semiconductor material walls alternate with oneanother along a second direction which intersects the first direction.The semiconductor material walls comprise a first semiconductormaterial, and the insulative walls comprise insulative material. Thestructure comprises a second semiconductor material under the dielectricbonding region. The structure has a planarized surface extending acrossthe semiconductor material walls and the insulative walls. Trenches areformed which extend downwardly into the semiconductor material walls andthe insulative walls. The trenches extend along the second direction.The trenches form semiconductor material pillars from upper regions ofthe semiconductor material walls. The semiconductor material pillars areover lower regions of the semiconductor material walls. The lowerregions are semiconductor material rails which extend along the firstconductive lines. Sidewall edges of the semiconductor material pillarsare exposed within the trenches, and top edges of the semiconductormaterial rails are exposed within the trenches. Dielectric material isformed along the exposed sidewall edges of the semiconductor materialpillars and along the exposed top edges of the semiconductor materialrails. Second conductive material is formed within the trenches andadjacent the dielectric material. The second conductive material isconfigured as second conductive lines which extend along the seconddirection. Memory structures are formed over the semiconductor materialpillars.

Some embodiments include a method of forming integrated circuitry. Astructure is formed to comprise first conductive lines over a dielectricbonding region. The first conductive lines extend along a firstdirection. The structure comprises conductive beams over the firstconductive lines, and spaced from the first conductive lines byinsulative regions. The conductive beams comprise conductive materialand are configured as downwardly-opening container shapes. Each of thedownwardly-opening container shapes includes a pair of sidewall regions,and includes a top region extending across the sidewall regions. Theconductive beams are spaced from one another by semiconductor materialwalls. Gate dielectric material is between the semiconductor materialwalls and the conductive beams. The conductive beams and thesemiconductor material walls extend along a second direction whichintersects the first direction. The conductive beams and thesemiconductor material walls alternate with one another along the firstdirection. The semiconductor material walls have bottom surfaces withfirst and second regions. The first regions are over top surfaces of thefirst conductive lines, and the second regions are between the firstregions. The semiconductor material walls comprise a first semiconductormaterial. The structure comprises a second semiconductor material underthe dielectric bonding region. Openings are formed to extend downwardlythrough the semiconductor material walls. The openings formsemiconductor material pillars from the semiconductor material walls.The semiconductor material pillars comprise the first regions along thebottom surfaces of the semiconductor walls. The openings are filled withinsulative material. The first semiconductor material, the conductivematerial and the insulative material are polished. The polishing removesthe top regions of the conductive beams and thereby forms spaced-apartsecond conductive lines from the sidewall regions of the conductivebeams. The polishing forms a planarized surface which extends across thesecond conductive lines, the semiconductor material pillars and theinsulative material. Upper surfaces of the second conductive lines arerecessed relative to the planarized surface. Memory structures areformed over the semiconductor material pillars.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

I claim:
 1. A method of forming integrated circuitry, comprising:forming a structure having first conductive lines over a dielectricbonding region; forming pillars in direct physical contact with an uppersurface of the first conductive lines and extending upwardly from thefirst conductive lines, the pillars having sidewalls extendingvertically from the first conductive lines to an uppermost pillarsurface, the entirety of the sidewalls comprising semiconductivematerial; forming second conductive lines over the first conductivelines and extending along the sidewalls of the pillars; the firstconductive lines extending along a first direction, and the secondconductive lines extending along a second direction which intersects thefirst direction; forming memory structures over the pillars, the memorystructures being within a memory array; forming third conductive linesover the memory structures; the third conductive lines extending alongthe first direction; individual memory structures of the memory arraybeing uniquely addressed through combinations including the first,second and third conductive lines; and wherein the first conductivelines are incorporated into bitlines or source lines; the thirdconductive lines are incorporated into the other of bitlines and sourcelines; and the second conductive lines are incorporated into wordlines.2. The method of claim 1 wherein the memory structures are MRAM cells.3. The method of claim 1 wherein the semiconductive material ismonocrystalline silicon.
 4. The method of claim 1 wherein the memorystructures are STT-MRAM cells.
 5. The method of claim 1 furthercomprising forming a pair of n-type source/drain regions within each ofthe pillars.
 6. The method of claim 5 further comprising forming ap-type channel region within each of the pillars located between then-type source/drain regions.
 7. The method of claim 1 further comprisingforming a pair of p-type source/drain regions within each of thepillars, and forming a n-type channel region within each of the pillarslocated between the p-type source/drain regions.